We propose to continue carrying out studies on the developmental genetics of Dictyostelium discoideum. In particular we will continue our analysis of mutants resistant to the mitotic inhibitors CIPC, nocadozole and thiabendazole. Our biological characterization of these mutants has given results which are consistant with the interpretation that the mutants are defective in microtubule structure and/or organization. We are attempting to prove this by comparing the structure of wild type tubulin in Dictyostelium with that of the mutants. Initially, this will be done using two-dimensional gels. At the same time we will be pursuing our studies using spore shape mutants. We are continuing our biological characterization of these mutants and we are beginning studies to attempt to determine the nature of the biochemical lesions involved.